The present invention is related to a tape cassette having punched paper tape for providing output impulses according to the program of the punched holes on the paper tape.
In the field, programmed tapes are commonly used to control the operation of associated electrical or mechanical devices. In one specific embodiment, presently commercially available for use in the operation of time alarms at programmed intervals is a tape control system which includes an endless programmed tape and a program drum in the form of a sprocket having projections thereon which engage with perforations in the endless tape. As the sprocket is driven by associated clock equipment the programmed tape is advanced and the information provided on the tape is sensed by an associated readout mechanism. While such an arrangement is relatively simple in construction and use, one disadvantage is that the programmed tape tends to cling or adhere to the peripheral surface of the rotatable drum as well as to the drum projections. When this occurs, the programmed tape may ride the rotating drum past the normal point of departure and jamming or non-advancement of the tape will occur.
Such type of a tape control system also exhibits certain shortcomings when used with the lengthy tapes which accommodate larger amounts of programmed information, that is, whenever longer tapes are used it is necessary to provide numerous guide and tensioning rollers to insure reliable travel of the tape along an assigned path in the equipment. In addition, it is further necessary to provide a storage cabinet of considerable dimensions in order to house both the longer tape and the guide and tensioning rollers associated therewith. Cabinets for use in such a system typically have a dimension of about 1 foot 6 inches .times. 3 feet 0 inches. The guide and tensioning members, of course, represent additional cost and further introduce possible areas of malfunction such as tape drag. In addition, one or more of the rollers by reason of mishandling or wear may fall out of alignment with the rest of the rollers in the tape path. Either condition, that is, tape drag or roller misalignment may result in perforation tear on the tape with the consequent result that the tape may be laterally displaced from the assigned path of travel relative to the whole sensing readout mechanism. In such event, the system, of course, will fail to perform its intended function.